Liquid crystal device and electronic apparatus provided with the same

ABSTRACT

Reflective display and transmissive display are performed by driving liquid crystal in a predetermined area (region b) in a non-crossing region by using an oblique electric field. Light passed through the region b when a voltage is applied is shaded since the liquid crystal in the region b is driven. Accordingly, at a position of a second substrate  2   b  corresponding to the region b, it is not necessary to provide a shading film  22 . Consequently, a line width S 1  of the shading film  22  can be designed to be smaller compared to that of a conventional one, and hence, a high aperture ratio can be obtained.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.11/389,653 filed Mar. 24, 2006 which is a divisional of U.S. applicationSer. No. 11/008,803 filed on Dec. 9, 2004 (U.S. Pat. No. 7,161,646issued Jan. 9, 2007); which is a continuation of U.S. application Ser.No. 09/953,088, filed on Sep. 14, 2001 (U.S. Pat. No. 6,839,105 issuedJan. 4, 2005); which claims the benefit of foreign applications JPSN2001-253472, filed Aug. 23, 2001, and JPSN 2000-280806, filed Sep. 14,2000. The disclosures of the above applications are incorporated hereinby reference.

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

The present invention relates to liquid crystal devices for displayingimages such as letters and numerals by modulating light using liquidcrystal. The present invention also relates to electronic apparatusesusing the liquid crystal devices.

2 . Description of the Related Art

In recent years, reflective liquid crystal devices have been frequentlyused for display units of electronic apparatuses such as mobileapparatuses. Since a light source such as a backlight is not provided inthe reflective liquid crystal device, they have enjoyed the advantage ofreduced electric power consumption. However, since external light isused as the light source, there has been a problem in that the displaycannot be viewed in dark places. In view of the above situation, atransflective liquid crystal device has been provided in which thedisplay can be viewed in bright places using external light similar tothe reflective liquid crystal device and can also be viewed in darkplaces using light emitted from a light source such as a backlight.

FIG. 12 is a view showing a schematic structure of a conventionaltransflective liquid crystal device 100. The transflective liquidcrystal device 100 shown in the figure is an active matrix liquidcrystal device using TFD (Thin Film Diode) elements as a switchingelement.

In this transflective liquid crystal device 100, between an uppersubstrate 101 and a lower substrate 102 each having transparency andinsulating properties, liquid crystal 103 is enclosed by a frame-shapedsealing material (not shown in the figure), and accordingly, a liquidcrystal cell 110 is formed.

On the inside surface of the upper substrate 101, a plurality ofrectangular pixel electrodes having transparency formed of ITO or thelike is provided and is connected to metal wires (not shown in thefigure) via the TFD elements. In addition, at the outside surface sideof the substrate 101, a polarizer 121 and a retardation film 122 areprovided in this order from an observer side.

In addition, at the inside surface side of the lower substrate 102, atransflector 131, a black matrix or a black mask for absorbing light,that is, shading films 132, and counter electrodes 135 are sequentiallyprovided in this order, and at the outside surface side of the lowersubstrate, a retardation film 142, a polarizer 141, and a backlight 150are provided. Since other elements (such as color layers, an alignmentfilm, and a protective layer) constituting the transflective liquidcrystal device 100 are not specifically necessary for describing displayoperation of the transflective liquid crystal device, they are not shownin the figures, and the descriptions thereof are omitted.

In the transflective liquid crystal device 100 having the structuredescribed above, when external light from the observer side enters thedevice while the device is in the white display state, in an electrodeexisting area at which the pixel electrode 111 is provided on the uppersubstrate 101, as shown by a light path A, the incident light passesthrough the polarizer 121, the retardation film 122, the upper substrate101, the pixel electrode 111, the liquid crystal layer 103, and thecounter electrode 135 in this order and reaches the transflector 131,and the light reflected at the transflector 131 retraces the paththrough which it passed and is emitted from the polarizer 121 to theobserver side.

In contrast, in a non-electrode existing area at which the pixelelectrode 111 is not provided on the upper substrate 101, incident lightis absorbed by the shading film 132 provided at the lower substrate 102side as shown by a light path B.

In addition, when light is emitted from the backlight 150, in theelectrode existing area, as shown by a light path C, the emitted lightfrom the backlight 150 passes through the polarizer 141, the retardationfilm 142, the lower substrate 102, the transflector 131, the counterelectrode 135, the liquid crystal layer 103, the pixel electrode 111,the upper substrate 101, the retardation film 122, and the polarizer 121in this order and is emitted to the observer side.

In contrast, in the non-electrode existing area, emitted light isabsorbed by the shading film 132 provided at the lower substrate 102side as shown by a light path D.

As described above, in the conventional transflective liquid crystaldevice 100, a display is created by reflecting the light entered intothe liquid crystal layer 103 from the observer side at the transflector131 when the environment is bright, and on the other hand, when theenvironment is dark, a transmissive display is created by transmittingthe light emitted from the backlight 150 through the transflector 131.

Although the conventional transflective liquid crystal device has anadvantage in that a reflective display and a transmissive display canboth be created depending on the environment in which it is used, sincethe light loss rate of the conventional transflective liquid crystaldevice is high, there has been a problem in that the display image isdark. In addition, as well as the transflective liquid crystal device,it has also been demanded to increase the brightness of the displayimage of the reflective liquid crystal device and the transmissiveliquid crystal device.

In view of the situations described above, the present invention wasmade, and an object of the present invention is to provide a liquidcrystal device having a high aperture ratio and superior displayproperties and to provide an electronic apparatus provided with theliquid crystal device described above.

SUMMARY OF THE INVENTION

(1) To these ends, in a liquid crystal device of the present inventioncomprising a first electrode, a second electrode opposing and crossingthe first electrode, and liquid crystal provided between the firstelectrode and the second electrode, a shading film is provided outsidethe crossing region of the first electrode and the second electrode andseparated from the crossing region.

According to the liquid crystal device having the structure describedabove, since the shading film is not provided at a positioncorresponding to the crossing region of the second electrode nor at aposition opposing a region which is a part of the non-crossing regionand is in the vicinity of the crossing region described above, theaperture ratio is increased corresponding to the region described above,and hence, a bright display image can be created.

In the structure described above, when a potential difference isgenerated between the first electrode and the second electrode, in theregion which is a part of the non-crossing region and in the vicinity ofthe crossing region, an electric field (hereinafter referred to as anoblique electric field) is generated in an oblique direction so as toextend from the crossing region to the non-crossing region. Accordingly,the liquid crystal layer opposing the non-crossing region andcorresponding to the area at which the shading film is not provided isdriven by the oblique electric field described above.

Accordingly, when a voltage is applied between electrodes of a liquidcrystal device which is driven in a normally white mode, the liquidcrystal layer opposing the region, which is a part of the non-crossingregion of the second electrode and is in the vicinity of the crossingregion, is driven, and as a result, light passed through the areadescribed above does not leak outside. That is, shading is performed.

When a liquid crystal is driven using an oblique electric field, theremay be a concern in that disclination occurs due to the generation ofreverse-tilt domains. Accordingly, areas at which reverse-tilt domainsare not generated are studied beforehand even when an oblique electricfield is used for driving the liquid crystal, and based on the result ofthis study, the liquid crystal area at which liquid crystal is driven byan oblique electric field is determined. As described above, by limitingthe liquid crystal area which is driven by using an oblique electricfield, the occurrence of disclination can be prevented.

(2) Next, in another liquid crystal device of the present inventionhaving the structure of the liquid crystal device described in the above(1), a plurality of the crossing regions may be formed by providing atleast a plurality of the first electrodes or at least a plurality of thesecond electrodes, and the shading film is provided separated from eachof a pair of crossing regions adjacent to each.

In a typical liquid crystal device, a plurality of the crossing regionsof the first electrodes and the second electrodes is provided. In thestructure described above, the shading film may be provided separatedfrom each of the crossing regions. Accordingly, the aperture ratio ofthe display area of the liquid crystal device can be further increased.

(3) Next, another liquid crystal device of the present invention havingthe structure of the liquid crystal device described in the above (1) or(2) may further comprise a reflector provided so as to overlap thesecond electrode in plan view, and the shading film is provided betweenthe second electrode and the reflector.

When a reflective display is created, external light passes through theshading film twice, and hence, sufficient shading can be performed bythe shading film. In contrast, when a transmissive display is created,since light only passes through the shading film once, there may be aconcern whether sufficient shading can be performed or not. However, asthe liquid crystal device of the present invention, when the reflectoris provided in addition to the shading film, shading can be reliablyperformed while transmissive display is performed.

(4) Next, in another liquid crystal device of the present inventionhaving the structure of one of the liquid crystal devices described inthe above (1) to (3), the shading film may be provided so as to surroundthe crossing region described above. That is, an aperture region may beprovided in the shading film so as to surround the crossing region.

(5) Next, another liquid crystal device of the present invention havingthe structure of the liquid crystal device described in the above (3) or(4) may further comprise a color layer provided between the reflectorand the second electrode. Accordingly, a color display can be created,and in the case mentioned above, bright color display having a highaperture ratio can be performed.

(6) Next, another liquid crystal device of the present invention havingthe structure of one of the liquid crystal devices described in theabove (1) to (5) may further comprise a lighting device for illuminatingthe liquid crystal from the second electrode side. Accordingly, atransmissive display can be created by using the lighting device as abacklight, and in the case described above, a bright display can also becreated.

(7) Next, in another liquid crystal device of the present inventionhaving the structure of the liquid crystal device described in the above(6), the reflector may be a transflector for reflecting and transmittingincident light in a predetermined ratio. When the transflector is used,there may be a concern in that a display image becomes dark due to anincrease in light loss rate; however, when the area at which the shadingfilm exists is decreased as described in the present invention, a brightdisplay can be created even when the transflector is used.

(8) Next, in another liquid crystal device of the present inventionhaving the structure of the liquid crystal device described in the above(7), the reflector may be provided with an open portion therein in thecrossing region. Accordingly, since light may be supplied to the liquidcrystal layer via this open portion, a reflective display using thereflector or a transmissive display using the open portion may beselectively created.

(9) Next, in another liquid crystal device of the present inventionhaving the structure of one of the liquid crystal devices described inthe above (1) to (8), the first electrode may be connected to aswitching element, and the shading film may cover the switching element.As the switching element, for example, there may be considered atwo-terminal type element such as a TFD element or a three-terminalelement such as a TFT element.

This liquid crystal device is an active matrix liquid crystal devicehaving the structure in which a voltage applied to the liquid crystal iscontrolled for each pixel by the switching element. In the liquidcrystal device having this structure, switching elements are preferablycovered by the shading film, and as a result, the entire non-crossingregions can be substantially shaded.

(10) Next, in another liquid crystal device of the present inventionhaving the structure of one of the liquid crystal devices described inthe above (1) to (9), the first electrode, the second electrode, and theliquid crystal are set in a normally white driving state. The normallywhite state is an optical state in which when a voltage is not appliedbetween the first electrode and the second electrode with liquid crystalprovided therebetween, or when an OFF voltage is applied, white displayis performed, that is, transmitted light passes through a polarizer andis then viewed from the outside.

In the liquid crystal device set in a normally white driving state, whenan ON voltage is applied, an oblique electric field is generated in thenon-crossing region in the vicinity of the crossing region, and liquidcrystal in this non-crossing region is driven. Accordingly, even whenthe shading film is not provided corresponding to this non-crossingregion, light leakage to the outside can be prevented. That is, shadingcan be performed.

(11) Next, in another liquid crystal device of the present inventionhaving the structure of one of the liquid crystal devices described inthe above (1) to (10), the reflector may also be used as the firstelectrode or the second electrode or may be connected to the firstelectrode or the second electrode.

(12) Next, in another liquid crystal device of the present inventioncomprising a first electrode, a second electrode opposing and crossingthe first electrode, and liquid crystal provided between the firstelectrode and the second electrode, a shading film is provided outsidethe crossing region of the first electrode and the second electrode andseparated from the crossing region, wherein the liquid crystal is drivenby an electric field generated between the first electrode and thesecond electrode, and an oblique electric field is applied to the liquidcrystal existing in an area corresponding to the space formed betweenthe shading film and the crossing region.

Since the liquid crystal in the area described above is driven by anoblique electric field, light is not allowed to pass through this area,and as a result, without providing the shading film at a positioncorresponding to the non-crossing region in the vicinity of the crossingregion, shading can be performed by controlling the orientation of theliquid crystal.

(13) Next, another liquid crystal device of the present inventioncomprises a first substrate and a second substrate opposing each otherwith a liquid crystal layer provided therebetween, a first electrodeprovided on a surface of the first substrate at the liquid crystal layerside, a second electrode which is provided on a surface of the secondsubstrate at the liquid crystal layer side and has a crossing regioncrossing the first electrode and a non-crossing region not crossing thefirst electrode, a reflector for reflecting light incident from theoutside of the first substrate or incident from the outside of thesecond substrate, and a shading film which is provided on a surface atthe liquid crystal layer side of one of the first substrate and thesecond substrate and which has an aperture region having an areacorresponding to areas of the crossing region of the second electrodeand of a region which is a part of the non-crossing region and is in thevicinity of the crossing region.

In the liquid crystal device having the structure described above, sincethe shading film has an aperture region corresponding to the crossingregion of the second electrode and the region which is a part of thenon-crossing region and is in the vicinity of the crossing regiondescribed above, the aperture ratio is increased, and hence, a brightdisplay image can be created.

When a potential difference is generated between the first electrode andthe second electrode, the liquid crystal layer opposing the non-crossingregion and corresponding to the aperture region is driven by an obliqueelectric field which is generated so as to extend from the crossingregion to the non-crossing region. Accordingly, when a voltage isapplied to a liquid crystal device which is driven in a normally whitemode, the liquid crystal layer opposing the region which is a part ofthe non-crossing region and is in the vicinity of the crossing region isalso driven, and hence, light passed through this non-crossing regiondescribed above is not leaked outside.

In the case in which liquid crystal is driven using an oblique electricfield, there may be a concern in that disclination occurs due to thegeneration of reverse-tilt domains. Accordingly, areas at whichreverse-tilt domains are not generated are studied beforehand even whenan oblique electric field is used for driving the liquid crystal, andbased on the result of this study, a liquid crystal area at which theliquid crystal is driven by an oblique electric field is determined. Asdescribed above, by determining the liquid crystal area at which liquidcrystal is driven by an oblique electric field, the occurrence ofdisclination can be prevented.

(14) Next, in another liquid crystal device of the present inventionhaving the structure of the liquid crystal device described in the above(13), in response to the generation of a potential difference betweenthe first electrode and the second electrode, the liquid crystal layeropposing the non-crossing region and corresponding to the apertureregion may be driven by an electric field which is generated in anoblique direction so as to extend from the crossing region to thenon-crossing region.

(15) Next, in another liquid crystal device of the present inventionhaving the structure of the liquid crystal device described in the above(13) or (14), the reflector may be provided with an open portion forallowing light incident from the side opposite to the liquid crystallayer with respect to the second substrate to pass through.

(16) Next, in another liquid crystal device of the present inventionhaving the structure of one of the liquid crystal devices described inthe above (13) to (15), the first electrode may be a plurality of pixelelectrodes formed on the first substrate, the second electrode may be aplurality of counter electrodes in a stripe pattern formed on a surfaceat the liquid crystal layer side of the second substrate, and thecounter electrodes each has a sufficient electrode width to cross atleast the entire surface of each of the pixel electrodes.

(17) Next, another liquid crystal device of the present invention havingthe structure of one of the liquid crystal devices described in theabove (13) to (16) may further comprise a lighting device disposed at aside opposite to the liquid crystal layer with respect to the secondsubstrate.

(18) Next, in an electronic apparatus according the present inventioncomprising a liquid crystal device and a container for receiving theliquid crystal device therein, the liquid crystal device is a liquidcrystal device according to one of the above (1) or (17).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a schematic structure of atransflective liquid crystal device of an embodiment according to thepresent invention;

FIG. 2 is a view showing a cross-sectional structure of the liquidcrystal device along the line A-A′ in FIG. 1;

FIG. 3 is a plan view for illustrating an electrode arrangement in onepixel of the liquid crystal device shown in FIG. 1;

FIG. 4 is a view for illustrating reflective display operation when avoltage is not applied to the liquid crystal device shown in FIG. 1;

FIG. 5 is a view for illustrating reflective display operation when avoltage is applied to the liquid crystal device shown in FIG. 1;

FIG. 6 is a view for illustrating transmissive display operation when avoltage is not applied to the liquid crystal device shown in FIG. 1;

FIG. 7 is a view for illustrating transmissive display operation when avoltage is applied to the liquid crystal device shown in FIG. 1;

FIG. 8 includes views for illustrating modified examples of arrangementof a shading film 22;

FIG. 9 is a block diagram showing an electrical structure of anelectronic apparatus of an embodiment according to the presentinvention;

FIG. 10 is a perspective view showing an example of a personal computerwhich is an electronic apparatus of another embodiment according to thepresent invention;

FIG. 11 is a perspective view showing an example of a mobile phone whichis an electronic apparatus of still another embodiment according to thepresent invention;

FIG. 12 is a view showing a cross-sectional structure of an example of aconventional liquid crystal device;

FIG. 13 is a view showing a cross-sectional structure of a liquidcrystal device of another embodiment according to the present invention;

FIG. 14 is an enlarged plan view showing one picture element portion orone pixel portion in a display area of the liquid crystal shown in FIG.13;

FIG. 15 is an enlarged perspective view showing one picture elementportion or one pixel portion in the display area of the liquid crystalshown in FIG. 13;

FIG. 16 is a view showing a cross-sectional structure of a liquidcrystal device of still another embodiment according to the presentinvention; and

FIG. 17 is an enlarged plan view showing one picture element portion orone pixel portion in a display area of the liquid crystal shown in FIG.16.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, with reference to the figures, embodiments of the presentinvention will be described. Although the embodiments described beloware modes of the present invention, the present invention is not limitedthereto, and modifications may be optionally made without departing fromthe scope of the present invention.

FIG. 1 is a perspective view showing a schematic structure of atransflective liquid crystal device 1 according to this embodiment, andFIG. 2 is a cross-sectional view taken along the line A-A′ of thetransflective liquid crystal device 1 shown in FIG. 1. In FIG. 2, forthe convenience of illustration, only one pixel electrode 5 is shown inthe figure; however, in the actual liquid crystal device, a plurality ofpixel electrodes 5 are formed on a first substrate 2 a. In addition, thetransflective liquid crystal device 1 of this embodiment is an activematrix liquid crystal device using two-terminal switching elementsrepresented by TFD (Thin Film Diode) elements; however, it is notintended that this embodiment is limited thereto, and this embodimentmay also be applied to, for example, an active matrix liquid crystaldevice using three-terminal switching elements represented by TFT (ThinFilm Transistor) elements or a passive matrix liquid crystal device.

As shown in FIGS. 1 and 2, in this transflective liquid crystal device1, between a first substrate 2 a and a second substrate 2 b each havingtransparency and insulating properties, a liquid crystal layer 3composed of nematic liquid crystal having a predetermined twist angle isenclosed by a frame-shaped sealing material (not shown in the figure),and hence, a liquid crystal cell 4 is formed.

On the inside surface of the first substrate 2 a, a plurality ofrectangular pixel electrodes 5 having transparency composed of ITO orthe like is formed, and each pixel electrode 5 is connected to a metalwire 6 via a two-terminal switching element such as a TFD element 9. Onthe surfaces of the pixel electrodes 5, an alignment film 10 a isformed, and this alignment film 10 a is processed by a rubbing treatmentin a predetermined direction. In addition, at the outside surface sideof the first substrate 2 a, a polarizer 7 a and a retardation film 8 aare formed in this order from the upper side in the figure.

In addition, at the inside surface side of the second substrate 2 b,transflector 21, shading films 22 formed as a black matrix or a blackmask, color layers 23, counter electrodes 24 used as second electrodes,and an alignment film 10 b are sequentially formed in this order.

The counter electrode 24 is composed of the same material as that forthe pixel electrode 5 formed on the first substrate 2 a, that is, thecounter electrode is composed of a conductive layer having transparencycomposed of ITO or the like, and is formed in a strip shape, when viewedin the direction indicated by an arrow B, so as to cross each pixelelectrode 5 in the lateral direction in FIG. 2. On the surfaces of thecounter electrodes 24, similar to the pixel electrode 5 described above,an alignment film 10 b is formed, and this alignment film 10 b isprocessed by rubbing treatment in a predetermined direction.

The color layer 23 has a predetermined pattern such as a deltaarrangement of three colors, R (red), G (green), and B (blue). Theshading film 22 is formed of a shading material such as chromium orchromium oxide and serves to prevent a decrease in contrast by shadinglight. A line width S1 of the shading film 22 of this embodiment isdesigned to be smaller than a line width S0 of the shading film 132 usedin the conventional liquid crystal device 100 shown in FIG. 12 by alength “d”. The shading film 22 thus designed is provided at a distance“d” from the crossing region (that is, the area where the electrodesexist) of the pixel electrode 5 and the counter electrode 24.

The transflector 21 is formed of a metal layer having reflectivitycomposed of, for example, aluminum or silver, and the transflectorreflects the light incident from the first substrate 2 a and allows thelight emitted from a lighting device 12 to pass through. In thetransflector 21, there are provided open portions 21 a which are in theform of, for example, a fine square aperture or a rectangular slit, orwhich are formed of fine defects or the like dotted in the transflector21. Accordingly, the light emitted from the lighting device 12 isallowed to pass through the transflector.

At the outside surface side of the lower substrate 2 b, a polarizer 7 band a retardation film 8 b are provided in this order from the lowerside in FIG. 2. In addition, behind the polarizer 7 b (that is, thelower side in FIG. 2), the lighting device 12 is disposed which has afluorescent tube 13 emitting white light and a light guide plate 14having edges along the fluorescent tube 13 for receiving light. In thisembodiment, the lighting device 12 is used as a backlight.

The light guide plate 14 is a transparent plate composed of an acrylicresin or the like having a roughened surface on the entire backside ofthe plate for scattering light and is formed for receiving light emittedfrom the fluorescent tube 13 at the edges in order to emit approximatelyuniform light to the upper side in FIG. 2. As a light source, inaddition to the fluorescent tube 13, a LED (light emitting diode), EL(electroluminescence), or the like may be used.

The transflective liquid crystal device 1 according to this embodimentis primarily formed of the constituent elements described above. Next,operation will be described with reference to FIGS. 1 to 3 when avoltage is applied to the transflective liquid crystal device 1 havingthe structure described above.

FIG. 3 is a plan view for illustrating the arrangement of electrodesprovided in one pixel in the display area of the transflective liquidcrystal device 1. As described above, on the surface of the pixelelectrode 5 and on the surface of the counter electrode 24, thealignment films 10 a and 10 b (see FIG. 2) are formed, respectively, anda rubbing treatment, that is, a treatment for determining theorientation direction of liquid crystal molecules when no voltage isapplied thereto, is performed for the alignment films 10 a and 10 b.

As can be seen in FIGS. 1-3 the pixel electrodes 5 are formed in anarray of spaced rectangular patterns whereas the counter electrodes 24are in the form of planar strips or sheets that vertically overlap oneor more of the individual pixel electrodes 5. These overlapping regionsare often referred to as crossing regions in this description eventhough they do not physically touch each other, the pixel electrodes 5and counter electrodes 24 being vertically separated by liquid crystallayer 3. Thus, the terms overlapping regions and crossing regions shouldbe construed the same.

In this embodiment, since the rubbing direction R5 for the pixelelectrode 5 and the rubbing direction R24 for the counter electrode 24are orthogonal to each other, the liquid crystal molecules rangingbetween the electrodes are controlled to be gradually twisted so as toform an angle of 90°. The liquid crystal cell described above isgenerally called a TN cell, and the liquid crystal molecules enclosed inthis liquid crystal cell each have a small tilt angle (that is, apretilt angle) along the rubbing direction.

When a voltage is applied between the pixel electrode 5 and the counterelectrode 24, as shown in FIG. 2, an electric field is generated in thecrossing region in the direction perpendicular to both substrates 2 aand 2 b. In addition, in the non-crossing region (that is, innon-electrode existing area), an electric field (hereinafter referred toas an oblique electric field) is generated in an oblique direction so asto extend from the crossing region to the non-crossing region.

In this embodiment, the liquid crystal is twisted at 90°. This isbecause it puts emphasis on a transmissive display mode. To put emphasison a transmissive display mode on a transflective liquid crystal devicewith switching elements, such as TFD elements or TFT elements, thetwisted angle is set between 55° or more and less than 120°. On thecontrary, to make displays with an emphasis on a reflective displaymode, the twisted angle is set between 0° or more and less than 80°.Further, an angle between 20° or more and less than 70° makes balanceddisplays possible in both the transmissive display mode and reflectivedisplay mode. To set these kinds of twisted angles, the crossing angleof rubbing directions R5 and R24 is set so as to achieve the desiredtwisted angle.

As a result, the orientation directions of the liquid crystal molecules(region a) in the crossing region and the liquid crystal molecules(region b) in a region which is a part of the non-crossing region and isin the vicinity of the crossing region are changed so as to increase thepretilt angle toward the generated electric field, and hence, thetwisted state of the liquid crystal molecules disappears. Since atransmissive state of light incident on the liquid crystal layer 3 ischanged in accordance with the change in orientation direction of theliquid crystal molecules in the liquid crystal layer 3, when theelectric field intensity is controlled by adjusting a voltage appliedbetween the pixel electrode 5 and the counter electrode 24, a desiredtransmittance can be obtained.

In the transflective liquid crystal device 1 of this embodiment, atransmissive display and a reflective display are created by driving theliquid crystal using not only the electric field generated perpendicularto both substrates 2 a and 2 b but also using the oblique electric fieldgenerated so as to extend from the crossing region to the non-crossingregion.

However, when the liquid crystal is driven by using an oblique electricfield, there may be a concern in that display defects (that is,disclination) occur due to the generation of reverse-tilt domains (thatis, the generation of an area in which liquid crystal molecules stand upin the direction opposite to that in which the liquid crystal moleculesshould stand up). Accordingly, regions at which reverse-tilt domains arenot generated are studied beforehand even when an oblique electric fieldis used for driving liquid crystal molecules, and based on the result ofthis study, the region b (that is, the area at which liquid crystalmolecules are driven by using an oblique electric field) is determined.As described above, by determining the region b, the occurrence ofdisclination can be prevented.

Next, display operation of a transflective liquid crystal device 1having a determined area for driving liquid crystal by an obliqueelectric field will be described with reference to FIGS. 4 to 7.

FIGS. 4 and 5 are views for illustrating reflective display operation,and FIGS. 6 and 7 are views for illustrating transmissive displayoperation. In FIGS. 4 to 7, in order to avoid complicated figures, onlyconstituent elements necessary for description are shown in the figure,and the other constituent elements are omitted. In addition, thedescription below is based on the case in which the device is driven ina normally white mode.

As shown in FIG. 4, in the case in which external light enters theliquid crystal cell from the observer side when no voltage is applied,the external light passes through the polarizer 7 a, the retardationfilm 8 a, and the like and further passes through the liquid crystallayer 3. External light passed through the liquid crystal layer 3 otherthan that absorbed by the shading film 22 shown by a light path creaches the transflector 21, and the light reflected at the transflector21 retraces the path through which it passed and is emitted from thepolarizer 7 a to the observer side (a light path a and a light path b inFIG. 4).

As described above, in the transflective liquid crystal device 1according to this embodiment, among the external light rays incidentfrom the observer side, in addition to the light passed through liquidcrystal (region a) in the crossing region, the light passed throughliquid crystal (region b) in a region of a part of the non-crossingregion is emitted to the observer side via the polarizer 7 a.

In contrast, when a voltage is applied between the pixel electrode 5 andthe counter electrode 24, in FIG. 5, an electric field is generated inthe crossing region in the direction perpendicular to both substrates 2a and 2 b, and an oblique electric field is also generated in thenon-crossing region so as to extend from the crossing region to thenon-crossing region.

Accordingly, liquid crystal molecules not only in the region a but alsoin the region b stand up along the electric field and are oriented inthe same direction. As a result, as shown by light paths d and e in FIG.5, external light passed through the region a is absorbed by thepolarizer 7 a, and in addition, external light passed through the regionb is also absorbed by the polarizer 7 a. In addition, external lightincident from a position opposing the shading film 22 is absorbed by theshading film 22 as shown by a light path f in FIG. 5 as in the casedescribed above. As described above, in the case in which external lightenters the liquid crystal cell from the observer side when a voltage isapplied, the whole external light is substantially absorbed by thepolarizer 7 a, the shading film 22, and the like. Consequently, lightleakage to the observer side does not occur.

Next, transmissive display will be described with reference to FIGS. 6and 7. As shown in FIG. 6, in the case in which light is emitted fromthe lighting device 12 when no voltage is applied, light passed throughthe polarizer 7 b and the retardation film 8 b becomes predeterminedpolarized light and passes through the open portions 21 a provided inthe transflector 21. An area of the transflector 21 other than the openportions 21 a serves as a shading film for shading light emitted fromthe lighting device 12.

Light passed through the open portions 21 a other than that absorbed bythe shading film 22 shown by a light path i enters the liquid crystallayer 3 via the color layer 23 and the counter electrode 24, and afterthe light passes through the liquid crystal layer 3, it is emitted tothe observer side via the retardation film 8 a and the polarizer 7 a asshown by a light path g and a light path h.

In contrast, when a voltage is applied, as described above, an electricfield is generated in the crossing region in the direction perpendicularto both substrates 2 a and 2 b as shown in FIG. 7, and in addition, anoblique electric field is also generated in the non-crossing region soas to extend from the crossing region to the non-crossing region.

Accordingly, liquid crystal molecules not only in the region a but alsoin the region b stand up along the electric field and are oriented inthe same direction. As a result, as shown by a light paths j, the lightwhich is emitted from the lighting device 12 and passes through theregion a is absorbed by the polarizer 7 a, and in addition, the emittedlight passed through the region b is also absorbed by the polarizer 7 aas shown by a light path k.

In addition, external light incident from a position opposing theshading film 22 is absorbed by the shading film 22 as shown by a lightpath I as in the case described above. As described above, in the casein which light is emitted from the lighting device 12 when a voltage isapplied, the whole emitted light is substantially absorbed by thepolarizer 7 a, the shading film 22, and the like. Consequently, lightleakage to the observer side does not occur.

As described above, the transflective liquid crystal device 1 of thisembodiment performs reflective display and transmissive display bydriving liquid crystal (region a) in the crossing region and liquidcrystal (region b) in a region which is a part of the non-crossingregion and which is in the vicinity of the crossing region. In thisdevice, light passed through the region b when a voltage is applied isabsorbed by the polarizer 7 a and the like since the liquid crystal inthe region b is driven. Accordingly, at a position of the secondsubstrate 2 b corresponding to the region b, it is not necessary toprovide the shading film 22. As a result, the line width of the shadingfilm 22 can be designed to be smaller than that of a conventional one,and hence, a high aperture ratio can be obtained. In other words, whenreflective display is performed, the brightness of display image can beincreased by an increase in reflectance, and when transmissive displayis performed, the brightness of display image can be increased by anincrease in transmittance.

Heretofore, one embodiment of the present invention was described;however, the embodiment described above is merely an example of thepresent invention, and various applications and modifications may bemade without departing from the scope of the present invention.

For example, in the embodiment described above, the transflector 21provided with the open portions 21 a was described by way of example;however, instead of forming the open portion 21 a, a transflector 15 to20 nm thick may be formed so as to serve as a transflector having areflectance of approximately 85% and a transmittance of approximately10%.

In addition, in the embodiment described above, the pixel electrodes 5formed on the first substrate 2 a were described by way of example;however, the pixel electrodes 5 may be formed on the second substrate 2b.

In the embodiment described above, the transflective liquid crystaldevice capable of performing reflective display and transmissive displaywas described by way of example; however, for example, this embodimentmay be applied to a reflective liquid crystal device performing onlyreflective display or a transmissive liquid crystal device performingonly transmissive display. When the present invention is applied to areflective liquid crystal device and a transmissive liquid crystaldevice, particular structure and display operation thereof areequivalent to those in the case of the transflective liquid crystaldevice described above.

Furthermore, in the embodiment described above, as shown in FIG. 3, theshading film 22 is provided at a distance of d from a positioncorresponding to the periphery 5 a of the pixel electrode 5; however, ashading film 22 having a shape shown by FIG. 8( a) or FIG. 8( b) may beprovided on the second substrate 2 b. That is, in the region b shown inFIG. 2, as long as the shading film 22 is not provided at a part of anarea corresponding to the liquid crystal area which is driven by anoblique electric field, a shading film 22 of an any shape may beprovided on the second substrate 2 b.

Next, cases in which the transflective liquid crystal device 1 of thepresent invention is applied to various electronic apparatuses will bedescribed. In the cases described above, as shown in FIG. 9, theelectronic apparatus is primarily composed of a display informationoutput source 50, a display information processing circuit 51, anelectric power circuit 52, a timing generator 53, the transflectiveliquid crystal device 1, and a drive circuit 54.

Among the constituent elements described above, the display informationoutput source 50 includes memories such as a RAM (Random Access Memory),storage units such as various discs, and a synchronizing circuit whichsynchronizes and outputs digital image signals. In addition, in responseto various clock signals produced by the timing generator 53, thedisplay information output source supplies display information such aspredetermined format image signals to the display information processingcircuit 51. Next, the display information processing circuit 51 includesmany known circuits, such as amplifier/inverter circuit, a rotationcircuit, a gamma correction circuit, and a clamp circuit, executesprocessing of input display information, and supplies the image signalsthereof to the drive circuit 54 together with clock signals CLK. Ascanning line drive circuit (not shown) and a data line drive circuit(not shown) together with inspection circuits are collectively referredto as the drive circuit 54. In addition, the electric power circuit 52supplies predetermined electric powers to the individual constituentelements.

Next, an example will be described in which the transflective liquidcrystal device 1 of the embodiment described above is used in aparticular electronic apparatus. First, an example in which the liquidcrystal device is used in a mobile type personal computer will bedescribed. FIG. 10 is a perspective view showing the structure of apersonal computer. In this figure, a personal computer 60 consists of amain body 62 provided with a keyboard 61 and a liquid crystal displayunit 63. This liquid crystal display unit 63 is composed of atransflective liquid crystal device 1 provided with a backlight.Accordingly, in places where external light cannot be used at all, byturning on the backlight, a display can be viewed.

In addition, an example will be described in which this transflectiveliquid crystal device 1 is used in a mobile phone. FIG. 11 is aperspective view showing the structure of a mobile phone 70. In thisfigure, the mobile phone 70 consists of a plurality of operation buttons71 and the transflective liquid crystal device 1 described above. Thistransflective liquid crystal device 1 is also provided with a backlight.

In addition to the electronic apparatuses described above with referenceto FIGS. 10 and 11, there may be mentioned a liquid crystal television,a viewfinder type and a direct viewing type video tape recorder, a carnavigation apparatus, a pager, an electronic notebook, an electroniccalculator, a word processor, a workstation, a television phone, a POSterminal, an apparatus provided with a touch panel, or the like. To thevarious electronic apparatuses described above, the transflective liquidcrystal device can also be naturally applied.

FIG. 13 shows a liquid crystal device of another embodiment according tothe present invention, and more particularly, shows an embodiment inwhich the present invention is applied to an active matrix typetransflective liquid crystal device using TFD elements as a switchingelement.

A liquid crystal device 31 shown in the figure has a liquid crystal cell34 and a lighting device 12 used as a backlight. The lighting device 12has a fluorescent tube 13 as a light source and a light guide body 14which receives light from the fluorescent tube 13 and emits the light asplanar light.

The liquid crystal cell 34 has a pair of substrates 2 a and 2 b whichare bonded together at the peripheries thereof by a sealing material(not shown) so as to oppose each other, and liquid crystal is enclosedin a gap formed between the substrates 2 a and 2 b, that is, in a cellgap, whereby a liquid crystal layer 3 is formed.

On the surface of the first substrate 2 a at the liquid crystal side,there are provided a plurality of TFD elements 32 each composed of afirst TFD part 32 a and a second TFD part 32 b, a plurality of metalwires 33 each connected to one terminal of the TFD element 32, and aplurality of pixel electrodes 5 used as first electrodes each connectedto the other terminal of each of the plurality of TFD elements 32. Inaddition, on the individual constituent elements described above, analignment film 10 a is formed. Orientation processing such as a rubbingtreatment is performed for this alignment film 10 a. On the outsidesurface of the first substrate 2 a (that is, an upper side in FIG. 13),a retardation film 8 a is formed, and on the surface thereof, apolarizer 7 a is formed.

The plurality of metal wires is formed in parallel to each other on thesurface of the first substrate 2 a, that is, is formed in a stripepattern. Along the metal wires 33, the TFD elements 32 are formed atregular intervals, and the pixel electrodes 5 are formed adjacent to theindividual TFD elements 32. As a result, the plurality of pixelelectrodes 5 is arranged in a dot matrix on the surface of the firstsubstrate 2 a.

In monochrome display without using a color filter, i.e., a color layer,one pixel electrode 5 generally forms one pixel. In a color displayusing color layers including three primary colors, such as R (red), G(green), and B (blue), or C (cyan), M (magenta), and Y (yellow), onepixel electrode 5 forms one pixel, and three color pixels, R, G, and Bform one picture element.

A structure in the vicinity of the TFD element 32 is shown in FIG. 15 byway of example. A TFD element having a so-called back-to-back structureis shown in FIG. 15. In FIG. 15, the metal wire 33 has a three-layeredstructure composed of a first layer 33 a formed of, for example, TaW(tantalum-tungsten), a second layer 33 b formed of, for example, ananodized film, Ta₂O₅ (tantalum oxide), and a third layer 33 c formed of,for example, Cr.

In addition, the first TFD part 32 a and the second TFD part 32 b, whichform the TFD element 32, each have a three-layered structure composed ofa first metal layer 36 formed of TaW, an insulating layer 37 composed ofTa₂O₅ formed by anodization, and a second metal layer 38 formed of Cr,which is the same layer as the third layer 33 c of the metal wire 33.

When the first TFD part 32 a is viewed from the metal wire 33 side, alaminated structure of the second metal layer 38/the insulating layer37/the first metal layer 36 is formed, and when the second TFD part 32 bis viewed from the metal wire 33 side, a laminated structure of thefirst metal layer 36/the insulating layer 37/the second metal layer 38is formed. As described above, a pair of TFD parts 32 a and 32 b isoppositely connected electrically in series so as to form a TFD elementhaving a back-to-back structure, and hence, the switching properties ofthe TFD element can be stabilized. The pixel electrode 5 is formed of,for example, ITO so as to be connected to the second metal layer 38 ofthe second TFD part 32 b.

In FIG. 13, at the liquid crystal side of the second substrate 2 b, atransflector 21, a shading film 22 used as a black mask or a blackmatrix, color filter films, i.e., color layers 23, an overcoat film 38,counter electrodes 24, and an alignment film 10 b are sequentiallyformed in this order. A transflector 21 opposing the pixel electrode 5is provided with at least one aperture 21 at an appropriate position. Inaddition, on the outside surface of the second substrate 2 b, aretardation film 8 b is formed, and on the surface thereof, a polarizer7 b is formed.

In FIG. 13, the plurality of metal wires 33 each extends in thedirection perpendicular to the plane of this figure, and on the otherhand, the plurality of counter electrodes 24 each extends in the lateraldirection in FIG. 13 to cross the metal wires 33, and counter electrodesadjacent to each other are arranged in parallel so that the whole isformed into a stripe pattern.

Areas at which the pixel electrodes 5 exist, that is, electrode existingareas, form crossing regions with the counter electrodes 24. Each of thecrossing regions forms one pixel, and each color pattern of the colorlayer 23 corresponds to one pixel. The color layer 23 is formed of, forexample, three primary colors, R (red), G (green), and B (blue), whichform one unit for forming one picture element. That is three pixels formone unit for forming one picture element.

The first substrate 2 a and the second substrate 2 b are formed of, forexample, a glass or a plastic. In addition, the transflector 21 isformed of a light reflective material such as Al (aluminum). In order toobtain both light transmissive and light reflective properties, forexample, a process may be performed in which the thickness of thetransflector 21 is reduced or an open portion for light transmittance isprovided at an appropriate position in the transflector 21. In thisembodiment, a plurality of open portions 21 a is provided.

The color layers 23 are formed by applying a pigment using a knownmethod for forming color picture elements, for example, an inkjet methodor a pigment-dispersing method, to an optional pattern, such as a mosaicarrangement, a stripe arrangement, or a delta arrangement. In addition,the overcoat film 38 is formed by uniform coating of an optionaltransmissive resin material using, for example, a spin coating method ora roll coating method.

The pixel electrodes 5 and the counter electrodes 24 are formed by astep of forming a film composed of, for example, ITO (Indium Tin Oxide),by a known film-forming method, such as a sputtering method or a vacuumdeposition method, and a subsequent step of patterning the film by aphotoetching method, whereby a desired pattern of the electrodes areformed. The alignment films 10 a and 10 b are formed by a method, suchas a method of applying a polyimide solution followed by firing or anoffset printing method.

In this embodiment, the shading film 22 is formed of a shading materialsuch as chromium or chromium oxide and serves to shade light so as toprevent the degradation of contrast. The line width S1 of the shadingfilm 22 of this embodiment is designed to be smaller than the line widthS0 of the shading film 132 used in the conventional liquid crystaldevice 100 shown in FIG. 12 by a length “d” at each side. The shadingfilm 22 thus designed is provided at a distance of “d” from the crossingregion of the pixel electrode 5 and the counter electrode 24 as shown inFIG. 13. In addition, this shading film 22 is disposed in an areaindicated by oblique lines in FIG. 14 when viewed in plan view. As shownin the figure, the shading film 22 covers the TFD elements 32 used as aswitching element.

The liquid crystal device 31 according to this embodiment performsreflective display and transmissive display by driving liquid crystal inthe crossing region, i.e., in the region a, and by driving liquidcrystal in a region which is a part of the non-crossing region and is inthe vicinity of the crossing region, i.e., in the region b. In thedevice described above, light passed through the region b when a voltageis applied is absorbed by the polarizer 7 a and the like since theliquid crystal in the region b is driven. Accordingly, at a position ofthe second substrate 2 b corresponding to the region b, it is notnecessary to provide the shading film 22. As a result, the line width ofthe shading film 22 can be designed to be smaller than that of theconventional one, and a high aperture ratio can be achieved. In otherwords, when reflective display is performed, the display image can bebrighter due to improved reflectance, and when transmissive display isperformed, the display image can also be brighter due to improvedtransmittance.

FIG. 16 is a view showing a liquid crystal device of still anotherembodiment according to the present invention and, more particularly,showing the embodiment in which the present invention is applied to anactive matrix type reflective liquid crystal device using TFT (Thin FilmTransistor) elements, which is a three-terminal active element, as aswitching element.

A liquid crystal device 41 shown in this figure is formed by steps ofbonding a first substrate 2 a and a second substrate 2 b by a sealingmaterial at the peripheries thereof, and enclosing liquid crystal in agap formed by the first substrate 2 a, the second substrate 2 b, and thesealing material so as to form a liquid crystal layer 3.

The first substrate 2 a is formed of a glass, a plastic, or the like.TFT (Thin Film Transistor) elements 42, an active element used as aswitching element, are formed on the first substrate 2 a, and pixelelectrodes 5 used as first electrodes are provided above the TFTelements 42 with an organic insulating films 48 provided therebetween.On the pixel electrodes 5, an alignment film 10 a is formed, and rubbingtreatment is performed on this alignment film 10 a. The pixel electrode5 is formed of a light reflective conductive material, such as Al(aluminum) or Ag (silver).

The second substrate 2 b opposing the first substrate 2 a is formed of aglass, a plastic, or the like, and on this second substrate 2 b, colorfilters, i.e., color layers 23, are formed. In addition, there areprovided a counter electrode 24 used as a second electrode on the colorlayers 23 and an alignment film 10 b on the counter electrode 24. Thecounter electrode 24 is a sheet-shaped electrode which is composed ofITO (Indium Tin Oxide) or the like and is formed on the entire area ofthe second substrate 2 b.

The color layers 23 each has one color filter element, such as R (red),G (green), and B (blue), or C (cyan), M (magenta), and Y (yellow), atpositions opposing the pixel electrodes 5 provided at the firstsubstrate 2 a side. At positions which are adjacent to the color layers23 and do not oppose the pixel electrodes 5, a black mask or a blackmatrix, that is a shading film 22, is provided.

In this embodiment, the line width S1 of the shading film 22 is designedto be smaller than the line width S0 of the shading film 132 used forthe conventional liquid crystal device 100 shown in FIG. 12 by a length“d” at each side. The shading film 22 thus designed is provided at adistance of “d” from the crossing region of the pixel electrode 5 andthe counter electrode 24 as shown in FIG. 16. In addition, the shadingfilm 22 is disposed in an area shown by oblique lines in FIG. 17 whenviewed in plan view. As shown in FIG. 17, the shading film covers theTFT elements 42 used as switching elements.

The TFT element 42 comprises a gate electrode 46 formed on the firstsubstrate 2 a, a gate insulating film 47 which is formed on the gateelectrode 46 and which covers the entire area of the first substrate 2a, a semiconductor layer 49 provided above the gate electrode 46 withthe gate insulating film 47 provided therebetween, a source electrode 44disposed at one side of the semiconductor layer 49 with a contactelectrode 45 provided therebetween, and a drain electrode 43 at theother side of the semiconductor layer 49 with a contact electrode 44provided therebetween.

As shown in FIG. 17, the gate electrode 46 is extended from the gate busline 29. In addition, the source electrode 44 is extended from thesource bus line 28. A plurality of the gate bus lines 29 is formed inthe lateral direction of the first substrate 2 a and is disposed inparallel to each other at regular intervals in the longitudinaldirection. A plurality of source bus lines 28 is formed in thelongitudinal direction so as to cross the gate bus lines 29 with thegate insulating film 47 (see FIG. 16) provided therebetween and isdisposed in parallel to each other at regular intervals in the lateraldirection.

The gate bus line 29 is connected to a liquid crystal driving IC (notshown) and is used as, for example, a scanning line, and the source busline 28 is connected to another liquid crystal driving IC (not shown)and is used as, for example, a signal line. In addition, as shown inFIG. 17, the pixel electrode 5 is formed in a square area formed by thegate bus line 29 and the source bus line 28 excluding an area at whichthe TFT element 42 is formed.

The gate bus line 29 and the gate electrode 46 are formed of, forexample, chromium or tantalum. The gate insulating film 47 is formed of,for example, silicon nitride (SiN_(x)) or silicon oxide (SiO_(x)). Thesemiconductor layer 49 is formed of, for example, a-Si, polysilicon, orCdSe. The contact electrode 45 is formed of, for example, a-Si. Thesource electrode 44, the source bus line 28 integral therewith, and thedrain electrode 43 are formed of, for example, titanium, molybdenum, oraluminum.

The organic insulating film 48 is formed over the entire area of thefirst substrate 2 a so as to cover the gate bus lines 29, the source buslines 28, and the TFT elements 42. However, a contact hole 26 is formedin the organic insulating film 48 at a position corresponding to thedrain electrode 43, and via the contact hole 26, the pixel electrode 5and the drain electrode 43 of the TFT element 42 are electricallyconnected to each other. On an organic insulating film 48 on which thepixel electrode 5 is formed, an irregular pattern formed of regularly orirregularly repeated concavo-convex pattern is formed. As a result, thepixel electrode 5 formed on the organic insulating film 48 has a lightreflective pattern having an irregular pattern similar to that describedabove.

Since the liquid crystal device of this embodiment has the structuredescribed above, in FIG. 16, external light from the observer side, thatis, external light entered into the liquid crystal device 41 from thesecond substrate 2 b side passes through the liquid crystal 3 andreaches the pixel electrode 5 formed of a light reflective material, andsubsequently, the light is reflected at the electrode 5 and again entersthe liquid crystal 3. The orientation of the liquid crystal 3 iscontrolled in each pixel by a voltage applied between the counterelectrode 24 and the pixel electrode 5 selected by a scanning signal anda data signal. Consequently, the reflected light entered into the liquidcrystal is modulated in each pixel, and letters, numerals, and the likeare thereby displayed.

In the liquid crystal device 41 of this embodiment, liquid crystal in acrossing region, i.e., in the region a, and liquid crystal in a regionwhich is a part of a non-crossing region and is in the vicinity of thecrossing region, i.e., in the region b, are driven, whereby reflectivedisplay is performed. In this embodiment, light passed through theregion b when a voltage is applied is absorbed in a polarizer 7 a andthe like since the liquid crystal in the region b is driven.Accordingly, at a position of the second substrate 2 b corresponding tothe area b, it is not necessary to provide the shading film 22.Accordingly, the line width of the shading film 22 can be designed to besmaller than that of a conventional one, and hence, a high apertureratio can be obtained. In other words, when reflective display isperformed, a display image can be brighter due to improved reflectance.

In the first substrate 2 a shown in FIG. 16, since the height of aposition at which the TFT element 42 is formed is increasedcorresponding to the thickness of the TFT element 42, a cell gap at theposition is smaller than that at the other positions. In thisembodiment, since the region b in which an oblique electric field isgenerated is included in the position described above, the intensity ofthe oblique electric field is increased corresponding to the decreasedof cell gap, and hence, a sufficient shading effect can be obtained evenwhen the line width of the shading film 22 is further decreased. In thecase described above, when the line width of the shading film is furtherdecreased, the aperture ratio can be further increased, and hence, aneven brighter display can be created.

As has thus been described, according to the present invention, since anoblique electric field generated between the periphery of the firstelectrode such as a pixel electrode and the second electrode such as acounter electrode is used for driving liquid crystal, the shading filmcan be designed to be smaller, and as a result, the aperture ratio canbe increased.

1. A liquid crystal device comprising: a pair of substrates; a liquidcrystal layer between the substrates; an electrode; a reflector thatoverlaps the electrode in plan view at an overlapping region; a shadingfilm laterally spaced from the overlapping region in plan view so thatan edge of the shading film is separated from an edge of the overlappingregion by a gap, wherein the electrode serves as a common electrode andthe reflector serves as a pixel electrode.
 2. A liquid crystal devicecomprising: a pair of substrates; a liquid crystal layer between thesubstrates; an electrode; a reflector that overlaps the electrode inplan view at an overlapping region; a shading film laterally spaced fromthe overlapping region in plan view so that an edge of the shading filmis separated from an edge of the overlapping region by a gap; and athin-film transistor that controls application of voltage to thereflector, wherein the electrode serves as a common electrode and thereflector serves as a pixel electrode.
 3. A liquid crystal devicecomprising: a pair of substrates; a liquid crystal layer between thesubstrates; an electrode; a reflector that overlaps the electrode inplan view at an overlapping region; a shading film laterally spaced fromthe overlapping region in plan view so that an edge of the shading filmis separated from an edge of the overlapping region by a gap; andanother reflector adjacent to the reflector, the reflector and theanother reflector serving as pixel electrodes of adjacent pixels in apixel matrix, the shading film being laterally positioned between thereflector and the another reflector in plan view.
 4. A liquid crystaldevice comprising: a pair of substrates; a liquid crystal layer betweenthe substrates; an electrode; a reflector that overlaps the electrode inplan view at an overlapping region; a shading film laterally spaced fromthe overlapping region in plan view so that an edge of the shading filmis separated from an edge of the overlapping region by a gap, whereinthe electrode and the reflector are disposed on opposite sides of theliquid crystal layer.